Electric heater.



H. W. DENHARD.

ELECTRIC HEATER.

APPLICATION FILED 11111.30. 1911.

l, 1 7 1 1 04;. I Patented Feb. 8, 1916.

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m/flamw 3 H. W. DENHARD.

\ ELECTRIC HEATER.

APPLICATION FILED JAN.30, 19H.

1,171,104.- Patented Feb. 8,1916.

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UNITED STATES PATENT OFFICE.

HARRY W. DENHARD, 0F MILWAUKEE, WISCONSIN, ASSIG-NOR TO THE CUTLER-HAMMER MFG. 00., 0F MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

ELECTRIC HEATER.

Specification of Letters Patent.

Patented Feb. 8, 1916.

To all whom it may concern:

Be it known that I, HARRY W. DENHARD, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofVisconsin, have invented new and useful Improvements in ElectricHeaters, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawing, forming apart of this specification.

This invention relates to electric heaters.

It is particularly applicable to electrically heated flat irons,although its application is not limited to this type of heaters.

The point of a flat iron is generally subjected to a relatively greateramount of work than any other portion of the working face of the ironand consequently the point tends to cool off morerapidly than theremainder of the working face.

One of the objects of this invention is to provide an improved form ofelectric heater having means for maintaining the entire working facethereof at the same temperature.

Another object is to provide an electric iron in which the point of theiron is maintained at the same temperature as the remainder of theworking face by the expenditure of a minimum amount of energy.

Another object is to provide an improvedheating element for use with aheat storing means for maintaining the entire working face of an iron ata uniform temperature.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an.

embodiment of the invention.

The view of the drawings are as follows:

Figure 1 is essentially a longitudinal sectional view of the iron. Fig.2 is a perspective view of a portion thereof, and Figs. 3 and 4 arerespectively a plan and perspective view of the heating element.

The iron comprises a hollow body portion formed in sections, 1 and 2.The section 1 forms the top and sides of the iron, while the section 2comprises a plate forming the working surface- To the body portion isattached a suitable handle 3. The bottom plate 2 is preferablyinterfitted with the sectlon 1. The two sections are secured together bymeans of a screw threaded rod 4 and nut 5. The rod 4 is threaded into aboss 6 provided on the upper side of the plate 2, while the nut 5 isexternal to the body portion.

Resting upon the upper face of the bottom plate 2, but separatedtherefrom by a layer of suitable insulating material is the electricalheating element or unit 7, which may assume various different forms. Thespecific structure of the element illustrated will be hereinafterdescribed. At its rear end the heating element is provided with terminallugs 8 having extensions 9 projecting through the top of section 1 andsuitably insulated therefrom. The extensions 9 project into a receptacle10 carried at the, rear of the iron, which receptacle electricallyconnects the heating element with the supply wires.

Superimposed upon the heatingelement, but separated therefrom by one ormore layers of suitable insulating material, is an iron plate 11 ofsubstantially the same shape and size as the bottom plate of the iron.The plate 11 is provided at its rear end with hollow bosses 12 throughwhich the terminals of the heating element are adapted to project, saidterminals being properly insulated from said bosses. The plate 11 has atwo-fold function, first, it gives the iron the requisite weight,second, being a heat absorbing body and being in close proximity to theplate 2, it acts as a heat reservoir, tending to maintain the workingface of the iron at a uniform temperature.

For a purpose hereinafter set forth, the

plate 11 is provided with an enlargement 13 adjacent to the point of theiron and said plate is preferably formed in two longitudinal sections aand b. The two sections a and b are preferably secured at their rearends to the plate 2 by screws 14, said screws being so located as not tocontact wlth the heating element 7. The two sections of the plate 11 arerecessed to clear the rod 4 and they are provided with lugs 15 adjacentsaid rod. Loosely mounted on the rod 4 is a clamping member 16 engagingthe lugs 15 on the sections a and Z) to hold said sections in a fixedrelation. Threaded onto the rod 4 is a nut 17 adapted to be turnedagainst the member 1.6 to firmly hold said member in engagement with thelugs on the plate 11 and by this means clamp the plate 11 and heatingelement against the bottom plate,2

of the iron.

If it be assumed that all portions of the plate ll-be heated to auniform temperature, it. will be apparent that owing to the pros visionof theenlargement 13 on the plate 11 a much greater volume of heat willbe stored in the nose of the iron than in the remainder thereof. It willalso be apparent that owing to the uniformity of temperature of allparts of the plate 11, all parts of the Working face of the iron willnaturally have a uniform temperature. On the other hand, the increasedvolume of heat stored in the nose of the iron will compensate for theincreased expenditure of heat at the point of the iron,

thereby tending to maintain the point at an even temperature with therest of the working face.

Inorder to insure uniform temperature of all parts of, the plate '11, itis necessary to supply the enlarged portion of said plate with a greatervolume of heat than the'portion of less cross sectional area. To meetthis condition, I have provided the heating element 7 with a portion 18particularly designed to give the increased volume of heat at the pointdesired. The portion 18 of the I heating element is adapted to bereceived between the two sections of the plate 11, the enlarged portionsof the two sections being slightly recessed to form a pocket therefor.Hereit should be noted that the portion 18 of the heating element mustbe'of such design as to supply the requisite amount of heat to theenlargement 13 and yet at the same time it must be so disposed and itsheating capacity must be so limited as not to disturb the uniformity ofthe temperature of the working face of the iron.

, In practice it would be possible to produce a heating element whichwould accomplish the required results in various different ways and ofvarious difi'erent materials. I prefer, however, to construct theelement in the manner illustrated in the drawing, because of thesimplicity thereof and cheapness of construction. This element may beproduced by stamping or punching the same from a single sheet ofconducting material havingthe proper degree of conductivity. It may bepunched at a single operation, the preferred shape and character of thepunching being illustrated in Fig. 3. This punching I comprises two likesections 20 and 21, which when arranged side by side as illustrated inFig. 4 produce a heating element of substantially the same shape andsize as the working face of the iron. Each of these sections is providedwith a plurality of transversely extending. slots, alte'rnate slotsextending from opposite sides thereof. This gives each section thecharacter of a reflexed bar or strip,

thereby providing a tortuous conducting path for the current traversinthe same. In addition to thesections 20 and 21, the elemeiit comprisestwo rectangular sections 22 ..ment, it will be obvious thata continuousand tortuous conducting path is provided throughout the entire area ofthe element, thereby giving'a maximum heating surface in a minimumspace. When the element has been punched as illustrated in Fig. 3, itmay be readily bent into the form shown in Fig. 4.

' whereby the sections 20 and 21 will form the heating portion for theworking face of the iron and the portions 22 and 23. the heating portionfor the enlargement 13.

It will thus be seen that a simple, eflicient heater has been providedin which the heating surface is maintained at a substantially uniformtemperature even though the heat demand on certain portions of theworking face is unequal. The heating unit which is employed distributesthe heat so that it is used efficiently to maintain the working surfaceof the heater at a uniform temperature. The heating unit is simple inconstruction and may be formed from a single piece of sheet-metal. Theentire heater may be inexpensively manufactured and easily assembled.The structure is not onlv inexpensive but it is durable and eiiicient.

It should be understood that the structure shown is for the purpose ofillustration only and that' other structures may be devised which embodythe invention and which are included-within the spirit and scope of theappended claims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is: I

1. In combination, an electrical heater having heat storing meansassociated therewith and havinga specially heated portion of increasedstoring capacity adjacent the portion of said heater dissipating themaximum amountof heat.

mitting' member, a heat storing member associated therewith having aportion of inof said members and an augmented quantity to said portionof increased storing capacity.

3. A heater having an electric heating element for heating the workingface thereof to a substantially uniform temperature and heat storingmeans heatedby said element and having a specially heated portion ofincreased storing capacity contiguous to the portion of the heaterdissipating the maximum amount of heat.

4. In an electrically heated device, in combination, an electricalheating element for heating the working face of the device to asubstantially uniform temperature, and heat-storing means heated by saidelement and having an increased storing capacity contiguous to theportion of the heated de- Vice dissipating the most heat, said elementhaving a portion for specially heating said heat-storing means at thepoint of its increased storing capacity.

5. In an electrically heated iron, in combination, a heat storing memberwithin the iron having a portion ofincreased storing capacity adjacentto the point of the iron and a heating element having a portion disposedbetween the working face of the iron and the portion of said memberhaving an increased storing capacity.

6. In an electrically heated iron, in combination, a heat storing memberwithin the iron having a portion of increased storing capacity adjacentto the point of the iron and a heating element having a portion forheating the point of the working face of the iron and another portionfor heating said portion of said heat storing member.

7. In an electrically heated iron, in combination, an electrical heatingelement for heating the working face of the iron to a substantiallyuniform temperature, a heat storing plate adjacent to the working faceand supplied with heat from said element, said heat storing plate havingan enlargement adjacent to the point of the iron and said element havinga portion for imparting an increased amount of heat to said enlargement.

8. In an electrically heated iron, in combination, a flat heatingelement arranged parallel to and in close proximity with the -workingface of the iron, a heat storing member superimposed upon said (heatingelement, said member having anenlarged portion of increased heat storingcapacity adjacent to the point of the iron and said heating elementhaving a perpendicularly disposed portion for heating-the enlargedportion of said member substantially independently of the working faceof the iron.

9. In an electrically heated iron, in combination, a heat storing membercontiguous to the Working face of the iron and having an enlargedportion of increased storing capacity adjacent to the point of the ironand an electrical heating element interposed between the Working face ofthe iron and said member, said element providing a conducting paththrough the enlarged portion of the heat storing member, whereby saidportion is heated substantially independently of the Working face of theiron and the remainder of said member.

10. A heating element for electric irons, comprising a single piece ofsheet metal, the main portion of said element comprising two sectionsconnected at one end by two perpendicularly disposed sections, saidelement being slotted throughout its entire length to provide a zigzagpath, beginning and terminating at the separated extremities of thesections of the main portion.

11. A portable heat generating and trans mitting device, comprising incombination,

at a substantially uniform temperature and for imparting an increasedamount of heat to the portion of said storing member having an increasedcapacity.

12. A portable electric heating device comprising, in combination, aheat transmittin'g member having a portion subjectable to an increasedheat demand, a heat reservoir member associated therewith and having aportion of increased storing capacity adjacent said portion of saidfirst mentioned member, and an electrical resistance element betweensaid members having a portion for maintaining said heat transmittingmember at a substantially uniform temperature and having a portion forimparting supplemental heat to the increased capacity portion of saidreservoir member substantially independently of the remainder of gaidmember and of said transmitting mem- 13. A portable heat generating andtransmitting device, comprising in combination, heat-transmitting andstoring means having portions of its working surface subject in usetovarying heat demands and having other portions of differentheat-storing capacities to compensate for said variations to theremainder of said means proportional scribe d my name in the presence oftwo Witto the heat storing capacity thereof whereby nesses.

. the Working face of said means is main- HARRY W. DENHARD.

tained at a substantially uniform temperai/Vitnesses: 5 ture during use.ALFRED HALVERSON,

In Witness whereof, I have hereuntoiag b- M.-R. FENNS.

